Receptor Tyrosine Kinase (RTK) signaling must be delicately controlled to ensure normal development. Recently, a novel player in the RTK pathway has been described - the Sprouty (Spry) proteins. These proteins fine-tune growth factor signaling, and could thus play a role in mediating different RTK-dependent outcomes within neural progenitor cells. Our long term goal is to understand Spry protein function in CNS stem cells. To address this we will describe the expression patterns of Spry1 and 2 in the developing and adult brain, and will use both in vivo and in vitro techniques to elucidate their function. Aim 1 will be to characterize the expression of Sprouty 1 and 2 in the embryonic cortex and the adult SVZ. To reveal Spry1 and Spry2 expression in forebrain germinal zones, we will examine mRNA and protein expression in the mouse cerebral cortex during development and in the adult SVZ using in situ hybridization and immunohistochemistry. In aim 2 we will determine the function of Sprouty1 and Sprouty2 in the embryonic cerebral cortex and adult SVZ. For this aim we will use both in vivo and in vitro techniques. For in vivo analysis we will use in utero electroporation to deliver Spry1 and 2 shRNA or overexpression constructs to the embryonic germinal zone. For in vitro assays, we will use a lentiviral delivery system to express Spry1 and 2 shRNA or overexpression constructs in embryonic cerebral cortical and adult SVZ cultures. These assays, coupled with the expression analysis, will allow us to determine the function of these novel RTK inhibitors in the developing embryonic cerebral cortex and adult SVZ. Neural progenitor cells (NPCs), which include neural stem cells (NSCs) have the potential for numerous therapeutic applications, including their direct use in neural repair and the possibility of modeling diseases that have a stem/progenitor cell component. RTK signaling critically impacts stem cell behavior throughout development, and alterations in RTK signaling are prevalent in CNS tumors. Hence it is important to understand RTK signaling in order to understand key aspects of normal stem cell biology and brain cancer cells, which may arise from a stem-like cell. [unreadable] [unreadable]